Depth of Field

Depth of Field in optics, particularly in film and photography is the distance in front and beyond the subject appearing in the focus. In one word it is the distance around focal plane that is considered to be sharp and it varies on the basis of camera type. When the lens axis is perpendicular to the plane of the image, the focus of the plane becomes parallel to the image plane, and the Depth of Field (DOF) extends between parallel planes on either side of the plane of focus (POF).

When the lens axis is no more perpendicular to the image plane, the POF is no longer parallel to the image plane. The rotation capability of POF is called Scheimpflug principle. The POF rotation is attained with camera movements. While the rotation of POF the near and far limits of Depth of Field are no longer parallel. At that time the Depth of Field becomes wedge-shaped. With tilt, the height of the Depth of Field increases with distance from the camera.

Rotating the POF with swing can be used for both the purpose of maximizing or minimizing the part of an image that is within the Depth of Field. Depth of field can be anywhere within a fraction of a millimeter to infinite. In those cases, where the entire image is required to have in focus a large DOF is appropriate.